1. Field of the Invention
The present invention relates to a backlight unit that emits light and to a liquid crystal display that uses the light from the backlight unit.
2. Background Art
Conventionally, in a backlight unit of a liquid crystal display, a diffusion plate is incorporated, and a prism sheet (lens sheet) for improving light collection capability is disposed on the diffusion plate. In such a backlight unit, there has been a problem of deformation of resin members (a diffusion plate, a lens sheet and the like) which is caused by heat of a light source, especially, deformation of the resin members that is caused by heat conducted according to on/off of the light source or heat radiation. This is because a squeak sound is generated by contact between a bent diffusion plate and the like and other members if such deformation (bend) occurs.
As a backlight unit that solves such problem, there is a backlight unit 182 that is disclosed in a patent document 1 and shown in FIG. 26. The backlight unit 182 sandwiches a relatively thin diffusion sheet 192 and a lens sheet SS′ located to cover the diffusion sheet 192 between a light guide plate 191 and a relatively thick diffusion plate DL′, so that both sheets 192 and SS′ are prevented from being bent. Besides, because the diffusion plate DL′ is supported by a surface of the light guide plate 191 via both sheets 192 and SS′, the diffusion plate DL′ is not easily bent. Accordingly, in such backlight unit 182, a squeak sound caused by bend of both sheets 192, SS′, and the diffusion plate DL′ is not generated.    [Patent document 1]: JP-A-2000-10095